Outbreaks of occupational neuropathies due to industrial chemicals are well documented. Many different chemicals are known to cause damage to the human nervous system. The recent outbreak of neuropathy among some workers in the Texas factory where the delayed neurotoxic insecticide leptophos waw manufactured and packaged is an example of occupational neuropathies. The possibility that those workers might have been exposed to other "neurotoxic" chemicals such as n-hexane, which was used in the plant, made it difficult to establish a relationship between leptophos exposure and worker symptoms. The purpose of the proposed study is to investigate the effect of inhaled hexacarbon solvent vapors, i.e., n-hexane, methyl n-butyl ketone, 2,5-hexanedione and 2,5-hexanediol on the production of delayed neurotoxicity by topically applied EPN (O-ethyl O-4-nitrophenyl phenylphosphonothioate) which is neurotoxic in hens. It is also proposed to study the effect of these solvents on the hepatic microsomal enzyme activities in hens. A study is proposed to investigate the effect of hexacarbon solvents on the pharmacokinetics and metabolism of 14C-EPN.